Project log4j Debugging on --verbose

Internal

• projects
• clad

Overview

This is a development pattern that routes log4j logging information to stderr if -v or --verbose command line options are used. Projects that implement it are clad, os-stats, gld, etc.

API

Use novaordis-utilities 4.2 or newer. novaordis-utilities 4.2.0 was the first release that contains StderrVerboseLogging.

For more details, see:

https://github.com/NovaOrdis/novaordis-utilities/blob/master/src/main/java/io/novaordis/utilities/logging/StderrVerboseLogging.java

Activate it as follows:

import io.novaordis.utilities.logging.StderrVerboseLogging;

...
if (verbose) {
    StderrVerboseLogging.enable();
}
...

StderrVerboseLogging comes with an init() static utility method that looks at the "verbose" system property and turns on stderr logging:

import io.novaordis.utilities.logging.StderrVerboseLogging;

StderrVerboseLogging.init();

Shell Wrapper Recommendations

The recommended way to pass the "verbose" information that was already identified by a bash wrapper to the JVM is to use:

-Dverbose=true

Typical bash wrapper code:

verbose=false
...
${verbose} && verbose_system_property="-Dverbose=true"

command="${java_bin} ... ${verbose_system_property} ${main_class}..."